Refrigerating apparatus



VREFRIRGERATING APPARATUS Filed Feb. 24, 1941 2 Sheets-Sheet 1 INSULATION 60 64 1 J76 76 74 66 .'INSU.LATIO BY Q INVENTOR. j

A. O. GROOMS REFRIGERATING APPARATUS Filled Feb; 24, 1941 2 Sheets-Sheet 2 INVENTOR. 0

April 18, 1944.

1 l1 1 V I l Patented Apr. 18, 1944 UNITED STATES PATENT OFFICE REFRIGERATING APPARATUS AlbertO. Grooms, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application February 24, 1941, Serial No. 380,252

7 Claims.

This invention relates to refrigerating apparatus and more particularly to control systems therefor.

At present, some refrigerators have food com- 22, which is separated by a removable glass shelf 7 or partition 24 from the freezing compartment 26 provided in the bottom of the cabinet. A common door 28 provides access to both compartpartments which are cooled through the walls ments and the remainder of both compartments thereof. Inasmuch as the public demands ice is enclosed within a metal inner liner member 30. freezing facilities in refrigerators, it is necessary The freezing compartment 26 is cooled princito operate the refrigerant evaporator at tempally through its bottom wall which is provided peratures below freezing. It is undesirable to with tubing 32 extending in serpentine fashion cool the walls of food compartments at such low over the greater portion of the bottom wall of temperatures. the inner linermember and constituting the first It is therefore an object of my invention to proportion of the primary evaporator. A second vide a refrigerating system wherein the temportion 34 of the primary evaporator is conperature of the walls of a compartment to be nected in series refrigerant circuit relation with cooled is controlled substantially independently the portion 32 and constitutes a finned heat of the temperature of the refrigerant evaporator. transfer member. It is another object of my invention to provide This finned heat transfer member. 34 as well' a simple means for controlling the temperature s h portion 32 are ocated in an a r C culatof the walls of a compartment to be cooled in acing passageway 36 which extends pw y to a cordance with the compartment temperature. centrifugal fan 38 directly driven by an electric It is another object of my invention to provide motor 40. The inlet to the fan 38 is at the ope a simple temperature regulating system for reguend of the centrifugal fan casing for receiving latingthe refrigeration of the walls of a coldair from the portion of the air circulating passage wall type of refrigerator. beneath the evaporator portion 32 and drawing It is still another object of my invention to the air t ou h t e fi ed portion 34 after which provide a two-temperature refrigerator in which the air is discharged from the outlet 42 of the fan the high temperature refrigeration is regulated upwardly thro h e air circulating passage 36 by the circulation of air which in turn is reguto the portion above the top of the inner liner lated'by a vibrating contact device. after which the air divides and passes down along Further objects and advantages of the present 30 the outside of both side walls of the inner liner invention will be apparent from the following demember 30 until it returns to the portion beneath scription, reference being had to the accompanythe evaporator portion 32. By this air circulating ing drawings, wherein a preferred form of the arrangement, the inner liner member 30 is surpresent invention is clearly shown. rounded by circulating cold air.-

In the drawings: The primary evaporator portions 32 and 34 are Fig. 1 is a vertical sectional view of a refrigsupplied with liquid refrigerant from the refri erator embodying somewhat diagrammatically erant condensing unit including a sealed motorone form of my invention; compressor unit 44 and the air-cooled condenser Fig. 2 is a view of the vibrating contact con- 46 from which liquid refrigerant is forwarded trol together with a wiring diagram. through the supply conduit 48 in heat exchange Fig. 3 is a vertical central section through relation withthe suction conduit 50 to a restrictor Fig. 1. 52 which controls the flow of liquid refrigerant Briefly, I have shown a refrigerator in which into the initial portion 32 of the evaporator. The the primary evaporator is provided at the botoperation of t refrigerant nd nsin unit is tom of the cabinet for freezing purposes. In controlled by a thermostatic switch 54 operated order to cool the food compartment, air cooled by in accordance with the temperature of a bulb 5B the primary evaporator is circulated in heat exmoun ed in heat exchange relation with the botchange relation with the outside of the inner tom of the inner liner 30. This switch may be liner member. This circulation is accomplished adjusted by the adjusting knob 58 to vary the by a centrifugal fan operating under the control so temperature of the portions of the primary evapof an adjustable temperature responsive vibrating orator over a considerable range. Theswitch 54 contact device. and the sealed unit 44 are connected in series Referring now to the drawings and more parin an electric circuit 60. The motor 40 for the fan ticularly to Fig. 1, there is shown a refrigerator 38 is connected in series with a control device 62 cabinet 20 containing an upper food compartment u in a circuit 64 which is connected in parallel with the circuit 50 so that it is controlled independently of the operation of the sealed motor-compressor 44.

The object in cooling the upper compartment 22 through the walls thereof is to cause the refrigeration to take place at a relatively high temperature through a sufllciently large surface so that the temperature of the air in the compartment 22 is very nearly as low as the temperature of the walls through which the refrigeration is accomplished. This temperature should be always above freezing and generally between about 35 and 42 F. This provides refrigeration under excellent conditions since by this method of cooling there is very little air circulation and very little moisture loss from foodstuff stored in the compartment. In order to maintain the temperature of the air within the compartment 22 as well as the temperature of the walls of the inner liner 30 within desirable limits I provide the control 62 in the form of a vibrating contact device better shown in Fig. 2.

In Fig. 2 the electric motor 40 is shown connected in the circuit 64. Thelmotor 40 is connected by a conductor 65 with' a stationary contact 68 and isaalscconnected by conductor 10 with an electric heater- 12 which is mounted upon a cantileven'supported bimetal strip 14 carrying at its free'end a movable contact 16. This bimetal strip T4 is anchored at the opposite end in a support 78'of insulating material. The bimetal strip M is so positioned that when heated it will move to close the contacts 68 and 16. The bimetal strip 14 may be adjusted by an adjusting. screw 80 which operates through a follower to apply a slight closing pressure upon the bimetal strip 14 adjacent its anchorage.

The operation of the vibrating contact device is as follows: When the contacts 68 and 16 are in the open position as shown, the current passing through the motor 40 will also pass through the high resistance heater 12 so that the amount of current flowing will be very small and will not be sufiicient to keep the motor 40 operating at its normal speed. However, the current which does pass through heater 12 will heat the bimetal strip 14 causing the bimetal strip 14 to bend to move the contact 16 into engagement with the contact 68 to allow current to flow through the conductor 66, contacts 68 and 1B and the bimetal strip 14 to the other side of the circuit 64. The bimetal strip 14 is made with sufllcient currentcarrying capacity that it will not be heated appreciably by the current flowing through it. However, it will be affected considerably by the temperature in the food compartment 22 and the higher the temperature. in the food compartment the greater portion of the time, the bimetal will hold the contacts 88 and 16 in the closed position. The closing of the contacts 68 and 16 will deenergize the heater I2 and allow the cooling of the bimetal strip 14 which in turn will allow the upward bending of the bimetal strip 14 to open the contacts 68 and 16.

This cycle of opening and closing will be re-' peated rapidly and will regulate the average amount of current flowing through the fan motor I so that the speed of the fan motor 40 will be controlled in accordance with the percentage of time the contacts 68 and 16 are in the closed position. This percentage of time in which the contacts 68 and 16 are in the closed position will be governed by the temperature of the compartment 22 which will exert a temperature influence upon the operation of the bimetal strip II. This temperature influence is sufficient to regulate the operation of the motor 40 in accordance with the temperature of the compartment 22 and the speed of the motor 40 will be so controlled by the vibrat- 5 ing contact thermostat 62 that suflicient current will flow through the motor to maintain the air circulation necessary to keep the food compartment 22 at the temperature for which the control device 62 is adjusted.

The motor 40 which drives the fan 38 will operate continuously since the vibration of the bimetal strip 14 will be sufllciently rapid that the motor will not start and stop but will operate continuously and will vary its speed only in ac- 15 cordance with the temperature of the compartment 22. By this simple means I am able to cool the food compartment 22 through the walls thereof at a desirable temperature and to regulate the temperature of the atmosphere within the food compartment in a very simple, convenient and inexpensive way.

While the form. of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be 25 adopted, all coming within the scope of the claims which follow:

What is claimed is as follows:

1. Refrigerating apparatus including an insulated cabinet containing a compartment to be cooled, a lining member surrounding the compartment, means forming a circulating passageway surrounding the compartment, a cooling unit in heat exchange relation with said circulating passageway, electrically operated means for circulating a fluid through said passageway into heat exchange relation with said cooling unit and the outside of said lining member, and temperature responsive means for varying the speed of opera tion of said electrically operated means gradually.

2. Refrigerating apparatus including an insulated cabinet containing a compartment to be cooled, a lining member surrounding the compartment, means forming a circulating passageway surrounding the compartment, a cooling unit in heat exchange relation with'said circulating passageway. electrically operated means for circulating a fluid through said passageway into heat exchange relation with said cooling unit and the outside of said lining member, and temperature responsive vibrating contact means for gradually varying the operation of. said electrically operated means.

3. Refrigerating apparatus including an insulated cabinet containing a compartment to be cooled, a lining member surrounding the compartment, means forming a circulating passageway surrounding the compartment, a cooling unit in heat exchange relation with said circulating passageway, electrically operated fan means for exchange relationship with said cooling'unit, and

electrical control means for gradually varying the supply of electrical energy to said fan means to gradually vary the output of the fan means.

circulating air through said passageway irito h eat 4. Refrigerating apparatus including aninsulated cabinetcontainin'g a compartment to be partment,

terior of said cabinet, and vibrating contact means forming a circulating passageway surrounding the compartment, a cooling system. including a cooling unit in heat exchange relation with said circulating passageway, electrically operated means for circulating a fluid into heat exchange relation with said cooling unit and the outside of said lining member, means responsive to temperature conditions of said cooling unit for controlling the cooling system, and separate means responsive to temperature conditions of said compartment for varying the operation oi said electrically operated means.

6. Refrigerating apparatus including a cabinet to be cooled, a cooling means for cooling the inmeans responsive to temperature conditions within said cabinet for gradually varying the rate of heat removal by said cooling means. f

'7. Refrigerating apparatus including a cabinet to be cooled, a cooling means'forcooling the interior of said cabinet, electrically operated fan means for circulating a fluid into heat exchange relationship with said cooling means and said cabinet, and vibrating contact means responsive to temperature conditions within said cabinet for gradually varying the operation of said fan means.

ALBERT O. GROOMS. 

